here is a new concpet image for an insectoid alien.
i did that with painter classic, that was one hard thing compared to photoshop.
any suggestions to the anatomy or to something on the creature itself?
especially i would need some advice to the legs, what kind of legs i should give him or her or it or whatever gender this thingy has.

This looks great! I really like the chest cavity and the bones that create the structure around the cavity. This reminds me of an ant-like alien. Maybe give it 2 sets of legs err 3 including the arms. Something like the way the ants stand in that movie ANTZ

To the arms/legs: well - you know, those things always have a deeper meaning, so it depends on what kind of alien this guy is. i.E.:
* if he's a primitive warrior you should probably give him hands similar to the front pair of legs of a praying mantis, because warriors tend to do a lot of fighting - primitive warriors don't have advanced weapons and so evolution does it's part.
* the more intelligent/advanced he is, the more humanoid are his hands, because he'd tend construct and handle his own weapons/stuff (guns, lasers, whatever...) and so he'd need "precision-tools" like humanoid hands - same goes for technicians/scientists etc.

try a similar approach for the feet and always have a look at his environment, like: his guts lie open, so he's probably used to a very humid surrounding, because else they'd drie out, so - living in a humid, swampy area he's probably got reptile-like feet with swimming-skins between the toes...